NKI100-40-XL bearing: complete specifications & equivalents

Specification table

Source: catalog reference (HR1 2026-09-25) · extracted 2026-09-30

Parameters extracted from the official FAG Rolling Bearings catalogue (HR1 2026-09-25); FAG® is a trademark of Schaeffler Technologies AG & Co. KG, used here for identification only — mpnbase is not an authorized FAG/Schaeffler distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at schaeffler.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the NKI100-40-XL model number is decoded

envelope 100×130×40 mm: 100 mm bore accepts a normal-tolerance machined shaft via the integral inner ring, with a thin 15.0 mm radial section packed with small-diameter needle rollers C is 143 kN and C0 290 kN at the 100 mm seat; the C/C0 ratio of 0.49 is characteristic of a needle bearing — high static rating relative to dynamic in a compact 130 mm outside diameter the fatigue load limit Cur is 51 kN, the limiting speed 4,200 r/min and the thermal reference speed 2,600 r/min; for small needle bearings the reference speed can exceed the kinematic limit, so the lower of the two governs the application dynamic capacity per millimetre of bore is 1.43 kN/mm and per millimetre of width 3.58 kN/mm — the reason 40 mm-wide needle bearings routinely replace much larger ball or roller positions mass is 1.33 kg (1330 g), just 0.26 g per mm² of projected 130×40 mm envelope, which keeps unbalanced forces low in fast-actuating linkages the 100 mm bore belongs to the large band, where HR1 full-complement and track-roller designs deliver their highest kilonewton ratings in slow, heavily loaded machinery NKI100/40-XL is supplied with a machined inner ring, so it mounts on an ordinary turned and ground shaft of normal tolerance — hardening the journal is not required Reading the NKI prefix: machined-ring needle bearing with inner ring, one roller row, capable of pure radial load at 143 kN C The -XL suffix marks the X-life execution: refined raceway topography and upgraded materials lift the basic ratings versus the non-X-life bearing at the same 100×130×40 mm envelope. Typical applications include rocker arms and valve trains, two-stroke and compressor piston pins and small electric motor accessory drives, where the 130 mm outside diameter and 143 kN dynamic rating match the duty. In rocker arms and valve trains the unit fits a compact 100 mm seat, and in two-stroke and compressor piston pins the 1.33 kg mass is part of the rotor inertia calculation. Designers also specify it for small electric motor accessory drives, relying on the 40 mm width and the published 290 kN static rating. Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting. Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Adding an IR inner ring changes the envelope logic: the same outer assembly then fits a smaller shaft — recheck bore, clearance and ratings when substituting.
• Without an inner ring the shaft is the raceway: 58–64 HRC and a ground, polished journal are mandatory, not recommendations.
• Keep the specified radial clearance; an oversized shaft or heavy interference removes it and the needles bind hot immediately.